Replacements: James Rochford, Luke Cahill, Ger Sweeney, Gearoid Ó Súilleabháin, Patrick Parfrey.
Replacements: Steve Collins, Adam Boland, Brian O'Callaghan, Cillian McAndrew, Gearoid McDonald.
Constitution made the early running in this clash of the heavyweights at Temple Hill, a game which marked Munster Under-20 scrum half Ryan Foley's debut at this level and he looked right at home in a productive half-back partnership with Darragh Lyons.
The pair stepped in for the injured Gerry Hurley and Johnny Holland, Constitution's regular number 10 who was sidelined through illness.
Cork Con made a statement of intent as Joe McSwiney's fine second-minute break paved the way for James Ryan's opening try which went unconverted.
Lansdowne edged ahead with penalties from Deasy after 12 and 16 minutes, but openside flanker Ryan's second try - the product of some excellent collective work from backs and forwards, with lock McSwiney again heavily involved - had the Leesiders back in front, with Lyons converting.
Lively winger Cathal Quinn added a third Cork Con try before the break, making it 19-6, and Lansdowne, who were beaten at home by UCD in the opening round, were facing an uphill task.
The game was put beyond the Dubliners' reach when a clever chip from Lyons produced Cork Con's bonus point score for centre Niall Kenneally.
They added a fifth try in the 58th minute when number 8 Willie Ryan crossed after a five-metre scrum and Lyons converted, with the comfortable home win sending Cork Con to the top of the table just ahead of their local rivals Dolphin.
Lansdowne mustered a late rally with unconverted tries from winger Cian Aherne and replacement Brian O'Callaghan, but Mike Ruddock's charges were well beaten on the day.
Ruddock said there is 'no cause for panic' in the Lansdowne ranks following two opening defeats, and they will be targeting a backlash when they host Young Munster on Saturday, October 26.
For the home side, new Cork Constitution head coach Tom Mulcahy can reflect on a very positive start to the season - with the display of youngster Foley drawing particular praise.
"I'm delighted for the kid (Foley), he did it in front of Mike Ruddock (the Ireland Under-20 head coach) and he really couldn't have performed better. His basics were fantastic, his passing, kicking, tackling, I'm delighted with him," Mulcahy told the Irish Examiner.
"I was a bit cheesed off at conceding two tries at the end although the game was over as a contest at that stage.
"Lansdowne ran away with the league last season and we were hugely worried when we became aware of the draw for the first couple of games, an away tie to Division 1B winners Ballynahninch and then Lansdowne, the champions.
"But to come out of those games with nine points is brilliant, it was a fantastic performance against the champions."
Referee: Leo Colgan (IRFU)